1. Field of the Invention
The present invention relates to a substrate processing apparatus for performing a treatment such as an oxide layer forming, thin layer forming, impurity diffusing, or etching on a substrate such as a silicon wafer.
2. Description of the Prior Art
Examples of substrate processing apparatuses include a batch type substrate processing apparatus configured to process a predetermined number of substrates at a time and a single-wafer type substrate processing apparatus configured to process substrates one by one.
In a single-wafer type substrate processing apparatus, a process chamber is provided to accommodate a substrate, a susceptor is installed in the process chamber as a substrate stage for placing the substrate thereon, the substrate is heated by a heater embedded in the susceptor, and process gas is introduced into the process chamber to treat the substrate.
Recent improvement in process yield has motivated the use of larger-diameter substrates, and accordingly, it has been required to increase the diameter of a susceptor and a heater buried in the susceptor.
However, due to restrictions such as manufacturing or maintenance restrictions, it is difficult to manufacture a large-diameter susceptor and a large-diameter heater, and it is also difficult to process a large-diameter substrate such as a 450-mm diameter substrate using a susceptor and a heater that are integrated into one piece.